A dispute between Brazil and the United States over the high cost of drugs used to treat people with HIV and Aids has taken a new twist.

Brazil has threatened to copy two of the most expensive Aids drugs if the makers do not lower their prices.

The US says copying the drugs violates patent rules and has complained to the World Trade Organisation (WTO).

The row has led to allegations that the drug companies are putting profits before the health of people in poor nations.

Brazil's HIV and Aids programme is widely regarded as one of the most successful in the world.

In contrast with many other countries, the number of infections in Brazil has plummeted and the government has been able to provide free treatment to 90,000 patients - something that would be unthinkable in other developing nations with miniscule health budgets.

Sanctions threat

Annual treatment now costs the Brazilian Government less than $5,000 per patient - compared to $12,000 in the US.

The involvement in the dispute of the WTO could eventually allow the US to impose sanctions on Brazil for violating patent rules giving the pharmaceuticals exclusive rights to produce the drugs.

The Americans say they are merely concerned about whose workers make the drugs and that their case is not about the health of Brazilians with HIV and Aids.

The dispute has led to questions about whether drug companies in rich nations are committed to combatting an epidemic which is decimating populations in developing countries.

The drug companies say they have already slashed prices in Brazil.

But the head of Brazil's successful Aids programme, Paulo Teixeira, says the drugs' firms profits are vast and they can well afford to lower them further.